Abstract

The wake turbulence structure of a cambered airfoil is studied experimentally, including the
effects of surface roughness, at different freestream turbulence levels in a transonic flow. As the
level of surface roughness increases, all wake profile quantities broaden significantly and nondimensional
vortex shedding frequencies decrease. Freestream turbulence has little effect on the
wake velocity profiles, turbulence structure, and vortex shedding frequency, especially
downstream of airfoils with rough surfaces. Compared with data from a symmetric airfoil, wake
profiles produced by the cambered airfoils also have significant dependence on surface
roughness, but are less sensitive to variations of freestream turbulence intensity. The cambered airfoil
also produces larger streamwise velocity deficits, and broader wakes compared to the
symmetric airfoil.